fix(deployer): wire pre-deploy backup into the unified dispatch path

auto_backup_before_deploy silently did nothing — MaybeBackupBeforeDeploy's
only caller was the legacy executeDeploy pipeline, removed in the
workload-first cutover. Reconnect it as maybeBackupBeforeDeploy(), invoked
from DispatchPlugin after the source resolves and before it runs, so the
setting fires for every source kind. Fail-open: a nil backuper, a
settings-load error, or a backup failure skips the snapshot without
blocking the deploy. Adds predeploy_backup_test.go asserting the wiring.

internal/deployer/deployer.go

@@ -100,20 +100,34 @@ func (d *Deployer) SetPreDeployBackuper(b PreDeployBackuper) {
 	d.backuper = b
 }
 
-// MaybeBackupBeforeDeploy creates a "pre-deploy" Tinyforge DB snapshot when
-// the setting is enabled. Failures are logged but do not abort the deploy:
-// missing a backup is preferable to refusing to ship a fix. Exposed so
-// Source plugins can opt into the same behaviour.
-func (d *Deployer) MaybeBackupBeforeDeploy(deployID string, settings store.Settings) {
-	if !settings.AutoBackupBeforeDeploy || d.backuper == nil {
+// maybeBackupBeforeDeploy takes a "pre-deploy" Tinyforge DB snapshot before a
+// deploy when the operator enabled auto_backup_before_deploy. It is called on
+// the unified deploy path (DispatchPlugin) so the setting actually fires — its
+// predecessor was orphaned when the legacy executeDeploy pipeline (its only
+// caller) was removed in the workload-first cutover, silently disabling the
+// setting.
+//
+// Fail-open: a nil backuper, a settings-load error, or a backup failure all
+// skip the snapshot without blocking the deploy — missing a backup is
+// preferable to refusing to ship a fix.
+func (d *Deployer) maybeBackupBeforeDeploy(workloadID string) {
+	if d.backuper == nil {
+		return
+	}
+	settings, err := d.store.GetSettings()
+	if err != nil {
+		slog.Warn("pre-deploy backup: load settings", "workload", workloadID, "error", err)
+		return
+	}
+	if !settings.AutoBackupBeforeDeploy {
 		return
 	}
 	backup, err := d.backuper.CreateBackup("pre-deploy")
 	if err != nil {
-		slog.Warn("pre-deploy backup failed", "deploy_id", deployID, "error", err)
+		slog.Warn("pre-deploy backup failed", "workload", workloadID, "error", err)
 		return
 	}
-	slog.Info("pre-deploy backup created", "deploy_id", deployID, "backup_id", backup.ID, "filename", backup.Filename)
+	slog.Info("pre-deploy backup created", "workload", workloadID, "backup_id", backup.ID, "filename", backup.Filename)
 }
 
 // SetDNSProvider sets the DNS provider for managing DNS records during deployments.

internal/deployer/dispatch.go

@@ -9,11 +9,10 @@ import (
 )
 
 // DispatchPlugin routes a DeploymentIntent for w to the matching Source
-// plugin. This is the new unified deploy path; the legacy executeDeploy
-// remains in place until Phase 6 ports image-deploy logic into
-// source/image. While both exist, callers must pick: webhook/registry
-// triggers + image deploys still go through the legacy path, while
-// /api/hooks/generic + the unified webhook ingress go through here.
+// plugin. This is the unified deploy path for every source kind (the legacy
+// executeDeploy pipeline was removed in the workload-first cutover). When the
+// operator enables auto_backup_before_deploy, a pre-deploy Tinyforge DB
+// snapshot is taken here, after the source resolves and before it runs.
 func (d *Deployer) DispatchPlugin(ctx context.Context, w plugin.Workload, intent plugin.DeploymentIntent) error {
 	if err := d.beginDispatch(); err != nil {
 		metrics.DeploysTotal.Inc(w.SourceKind, "rejected_draining")
@@ -29,6 +28,11 @@ func (d *Deployer) DispatchPlugin(ctx context.Context, w plugin.Workload, intent
 		metrics.DeploysTotal.Inc("unknown", "unknown_source")
 		return fmt.Errorf("dispatch %s: %w", w.Name, err)
 	}
+	// Optional operator-enabled pre-deploy DB snapshot. Fail-open: never
+	// blocks shipping a deploy. Runs before any source-internal idempotency
+	// check (e.g. the image source's same-tag short-circuit), so a same-tag
+	// redeploy still snapshots — "backup before every deploy attempt".
+	d.maybeBackupBeforeDeploy(w.ID)
 	err = src.Deploy(ctx, d.PluginDeps(), w, intent)
 	outcome := "success"
 	if err != nil {

internal/deployer/predeploy_backup_test.go

@@ -0,0 +1,107 @@
+package deployer
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+	"testing"
+
+	"github.com/alexei/tinyforge/internal/store"
+	"github.com/alexei/tinyforge/internal/workload/plugin"
+)
+
+// fakeBackuper records pre-deploy backup calls so the dispatch wiring can be
+// asserted. err (when set) simulates a backup failure.
+type fakeBackuper struct {
+	count    atomic.Int32
+	lastType atomic.Value // string
+	err      error
+}
+
+func (f *fakeBackuper) CreateBackup(backupType string) (store.Backup, error) {
+	f.count.Add(1)
+	f.lastType.Store(backupType)
+	if f.err != nil {
+		return store.Backup{}, f.err
+	}
+	return store.Backup{ID: "b1", Filename: "tinyforge-pre-deploy.db"}, nil
+}
+
+func setAutoBackup(t *testing.T, d *Deployer, enabled bool) {
+	t.Helper()
+	s, err := d.store.GetSettings()
+	if err != nil {
+		t.Fatalf("get settings: %v", err)
+	}
+	s.AutoBackupBeforeDeploy = enabled
+	if err := d.store.UpdateSettings(s); err != nil {
+		t.Fatalf("update settings: %v", err)
+	}
+}
+
+// Regression: the pre-deploy backup hook was orphaned after the cutover (no
+// caller on DispatchPlugin), making auto_backup_before_deploy a silent no-op.
+func TestDispatchPlugin_PreDeployBackup_FiresWhenEnabled(t *testing.T) {
+	resetFake(t)
+	d := newTestDeployer(t)
+	b := &fakeBackuper{}
+	d.SetPreDeployBackuper(b)
+	setAutoBackup(t, d, true)
+
+	if err := d.DispatchPlugin(context.Background(), sampleWorkload(), plugin.DeploymentIntent{}); err != nil {
+		t.Fatalf("dispatch: %v", err)
+	}
+	if got := b.count.Load(); got != 1 {
+		t.Fatalf("CreateBackup called %d times, want 1", got)
+	}
+	if bt, _ := b.lastType.Load().(string); bt != "pre-deploy" {
+		t.Fatalf("backup type = %q, want pre-deploy", bt)
+	}
+	if got := dispatchTestSource.deployCount.Load(); got != 1 {
+		t.Fatalf("Deploy ran %d times, want 1", got)
+	}
+}
+
+func TestDispatchPlugin_PreDeployBackup_SkippedWhenDisabled(t *testing.T) {
+	resetFake(t)
+	d := newTestDeployer(t)
+	b := &fakeBackuper{}
+	d.SetPreDeployBackuper(b)
+	setAutoBackup(t, d, false)
+
+	if err := d.DispatchPlugin(context.Background(), sampleWorkload(), plugin.DeploymentIntent{}); err != nil {
+		t.Fatalf("dispatch: %v", err)
+	}
+	if got := b.count.Load(); got != 0 {
+		t.Fatalf("CreateBackup called %d times, want 0 (setting off)", got)
+	}
+}
+
+func TestDispatchPlugin_PreDeployBackup_NilBackuperNoPanic(t *testing.T) {
+	resetFake(t)
+	d := newTestDeployer(t)
+	setAutoBackup(t, d, true) // enabled, but no backuper wired
+
+	if err := d.DispatchPlugin(context.Background(), sampleWorkload(), plugin.DeploymentIntent{}); err != nil {
+		t.Fatalf("dispatch must not panic/fail with a nil backuper: %v", err)
+	}
+	if got := dispatchTestSource.deployCount.Load(); got != 1 {
+		t.Fatalf("Deploy ran %d times, want 1", got)
+	}
+}
+
+func TestDispatchPlugin_PreDeployBackup_FailOpen(t *testing.T) {
+	resetFake(t)
+	d := newTestDeployer(t)
+	b := &fakeBackuper{err: errors.New("disk full")}
+	d.SetPreDeployBackuper(b)
+	setAutoBackup(t, d, true)
+
+	// A failed backup is logged but must NOT block the deploy.
+	if err := d.DispatchPlugin(context.Background(), sampleWorkload(), plugin.DeploymentIntent{}); err != nil {
+		t.Fatalf("deploy must succeed when backup fails (fail-open): %v", err)
+	}
+	if got := dispatchTestSource.deployCount.Load(); got != 1 {
+		t.Fatalf("Deploy ran %d times, want 1 (despite backup failure)", got)
+	}
+}